Trivalent compounds of titanium and method of making same



Patented Mar. 16, 1954 i 1- TRIVALENT COMPOUNDS OF TITANIUM AND METHOD OF MAKING SAME Eugene Wainer, Cleveland Heights, and Samuel Z. Cardon, Cleveland, Ohio, assignors, by mesne assignments, to Horizons Titanium Corporation, Princeton, N. J., a corporation of New Jersey No Drawing. Application January 17, 1952, SerialNo. 266,994

7 Claims.

The chemistry of the compounds of titanium in which the titanium exists in stable form at a valence less than 4 is obscure and very little known. Trivalent titanium compounds are important in the dye industry and are promising as a source of feed to reactions used for the preparation of metallic titanium, particularly through the medium of electrolysis. Economical methods of preparation of a variety of trivalent titanium compounds of titanium have not been available; and more important, such compounds have not been made in stable form in condition such that they will remain stable on exposure to the atmosphere. Finally and most important, trivalent compounds in solid form would oifer a particularly useful type for commercial purposes, and particularly if such solid forms melt at relatively low temperatures without decomposition.

In accordance with the present invention trivalent fluorine compounds of titanium are prepared in novel manner; and particularly alkali fluotitanates of titanium in which the titanium exists in a valence of 3. We have methods for making stable trivalent compounds of titanium by relatively simple reactions. In addition, we have also found means for preparing two novel compounds of trivalent titanium which are commercially useful. Other objects and advantages of the invention will be seen from the following description.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments ofthe invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

Our novel methods of procedure were originally devised for preparation of the trivalent titanium compound KzTiFs. We have also been able to prepare the novel compounds'KzTizFa and Ka'I'iFs. In these the titanium exists in a. valence of three; but more important is the fact that these compounds are prepared such that exceptional stability is found to exist so that the titanium compound oxidizes with difliculty.

We obtain our novel compounds and results through the medium of reaction of appropriate fluorine compounds on titanium monoxide. Titanium monoxide is a hard golden brown colored derivative of titanium. The material is a fairly good electrical conductor and the ostensible vaing this compound in suitable containers with the appropriate fluorine derivatives, a stable compound of titanium can be obtained and hydrogen is evolved in the reaction. This would indicate that the titanium present in the titanium monoxide is present in the valence of 2. Effective compounds for the purposes of this invention are the alkali metal compounds, and pref erably sodium and potassium compounds.

We have found a general procedure whereby these trivalent compounds of titanium can be made. In general, we react titanium monoxide with two fluorides, one an alkali metal fluoride, and the other an acid fluoride of a base of the class consisting of NH4 and elements of periodic group I whose atomic weight is less than 40, that is, sodium, potassium, lithium and ammonium acid fluorides. Thus, it may involve treatment of the titanium monoxide v ith hydrofluoric acid ina controlled atmosphere, then adding the proper quantity of an alkali fluoride such as potassium fluoride or sodium fluoride, evaporating to dryness in a controlled or inert atmosphere and then heating to fusion. Again it may involve theme of ammonium acid fluoride and potassium fluoride or other alkalifluorides mixed in dry form with the titanium monoxide and then heating. It is preferable again that this heating take place in a controlled atmosphere such as nitrogen to prevent the access of oxygen during this heating step. Products of such a reaction are the alkali fluotitanates in which the titanium is present in the valence of 3, water, ammonia, and hydrogen, and all of these latter three pass off as gases. If the amounts of potassium fluoride or other alkali fluorides are proper, stable compounds of formula KzTlFs, KsTiFc, or K2Ti2Fs may be made. The latter two compounds are more stable on fusion than the KzTiFs. Also it may involve the use of mixtures of potassium acid fluorides or other alkali acid fluorides plus an extra amount of a normal alkali fluoride plus the finely powdered titanium monoxide. This mixture is subjectedto heat in an inert or controlled atmosphere and the said product compounds are obtained with the concomitant evolution of water vapor and hydrogen. Of the three forms of reagent described above, the latter two are preferred. The alkali acid fluoride compounds may b employed in different formulae, of which, for example, the KFHF compound and the KF2HF compound are typical. types of reactions, the KF2HF compound is preferred since it is commercially available at low lence of titanium in this compound is 2. Onheat- .55 a cost.

For theseboiling of concentrated hydrofluoric acid in such.

crucibles for a period of a few minutes, then pouring out the hydrofluoric acid and evaporating the liquid film thus obtained to drynessand finally baking so as to insure the formationof thechemically stable difluorides of nickelor copper on the surface. In order that this typezof treatment be avoided, dense graphite maybe used if it .is.insert-; ed in a metal container which prevents access of air to the graphit when it is heated. The graphite container is fitted with a tight cover containing (an.

inlet and outlet. The input consists of dry pure nitrogen, and the outlet is made sufficientlynarrcw in diameter so that oxygen cannot diffuse back into the contents of the crucible while the materi-al is beingfiheated.

.In .carryingout .thereactions indicated .in the foregoing, the various ingredientsare mixed 'in dry form and "then put in the crucible. The mixture is then heated to a temperature range below' volatilization of the fluoride, via, .aroundthe boiling point of water, i. e., between 100 and 125 C., for a .periodof 15 to 25 minutes. The purpose of this preliminary heating is to make certain that most. of the relatively expensive fluorine compoundwhich is present is not decomposed and volatilized prematurely before it has an opportunity to react. with the titanium compound present. 'After this period of heating is complet'ed theiemperatm'e is raised to about 400 C. and the reaction continued until all tracesof gases such as hydrogen, ammonia, or water are eliminated. Both phases of the reaction; that is the preliminary heating-and .the finalx'heating, are

carried out in an inert atmosphere, such as nitrogen, nitrogen'being'fed into the reactiontzone. at the: rate of l to 2' liters 'perminute. The temperature of 400-5 00'C. is sufficient to carry the reaction to completion. and the end product of.

the reaction on cooling is usuallyjn the'form of a dark blue, purple, or purplish brown sintered mass. On exposure to the air, this sintered mass does not exhibit hygroscopic propertieswandr. is stable for further. handling.

The'following examples are illustrative of our method:

Example 1.-.-l75 grams of .ammonium 'acid fluoride-(this is slightly more than the theoretical amount in that the ammoniumacid fluoride :used generally contains a small amount of 'WatEII Of hydration) were mixed'with 135 grams or substantially pure titanium monoxide :andl -6 grams of .KF. Titanium monoxide Wasin the tformscf -200 mesh powder; The mixture was thenwpnt in a graphite crucible fitted with an outside nickel linerand a closely fitting top. An inlet tube was fastened throughthe lid, and an outlet. port roughly $41 in diameter was "also provided for-in the lid. Pure nitrogen'was fed into thecrucibleiat the rate of about 1 liter per minute. Afterallithe 'air had been displaced from the-crucible,=the assembly'was heated to about 120 0., and a-sthe temperaturebecame uniform the temperature was maintained for about minutes. After. this preliminary heatingperiod was completed, theitemperature was raised to 500 C. i In the-course of raising the temperature-of the container to this range. a noticeable-evolution of wateruand 'ammonia occurred as determined by the odor andappearance of the gas. Substantial amount of hydrogen were also evolved and if a lighted flame were brought in the vicinity of the port and the reaction Were-carried out-in theabsence of nitrogen, an explosion could result. The'reaction was continued until all evidence of steam or ammonia evolution ceased. This usually requires an hour of heating at a temperature of 500 C. The reaction mass was then cooled down to room temperature-under the atmospher of nitrogen, and

the-contents on opening the crucible were found to be .aesintered dark purplish mass weighing 325 grams. =In'view' of the ingredients which were used,-this:is practically a yield of the novel compound KzTizFsia Example 2...'Ihe ingredients and the reaction mixture were the same as in Example 1 except twice as much potassium fluoride was used, equivalent to 322 grams. 440 grams of the dark purple compound resulted, which is equivalent to a substantially' theoretical yield of -th'e compound KeYJEiiIEs.

Example 3..-Same.as in Example 1 except that 350- grams of potassium fluoride were used and the same procedure was carried'out as before except that 560 gramsof product were obtained equivalent-to the compound KsTiFe; The compounds KsTiFs and the compounds KzTizFs may be heated to fusion and on cooling are found substantially unchanged. Ir thecompound KeTiFs is heated to fusion, some decomposition-possiblyevolution of TlFs or of TiF-i takes placepas apparent from changes exhibited, and established. by analysis on cooling to roomtemperature.

Example -4.-Same as in Examplel except that 84 grams of sodium fluoridexwere used in place. of the potassium fluoride. 295 grams of product were obtained, equiyalent :zto the: compound NaeTizFa'.

Emumple 5'.295 grams of thercompoundKFZHF andaE-S grams of .zpotassiumufluoride weremixed with. 132 .grams :of :titanium .mcnoxide as in the previous ziexamplesx-z; Thisumixture was theater! as before through the two temperature rangesin an atmosphere" of nitrogen. .440 gramsiof product resulted;- substantially equivalent to 100:% yie1d 0f the 1 compound Kz'EiFti:

Example: s6.-+294 :gramszxiof the compound KNEE-P grams :of zpotassium fluoride-M32 grams of titanium monoxide were thoroughly mixed and'iieated in anfatmosphereof nitrogen as in Example I. ;.560-grams: :of product'resulted, equivalent to thexcompouncl KQTiFc whichds substantiallyf100%f yield:

- Example:-7 ;.Same as in Examplefi except't-hat '42 grams 'of sodium= fluoride .were' used in place of the :58 grams of potassium fiuoridei 410 grams "of -productnresulted, equivalent: to practically 100% yield of the compound NaKTiEsaa" a,

Example -:8.190-.--gramsz of the -compound NaF.2HE Zweremixed with '42 gramsof :NaF and 132 grams of 1:10;. I" The procedure in accordance with: Example 13 was'iollowed1andf380 grams :oi' producttobtained; substantially equivalent ta ta "theoretical :yield of 'thecompound NazTiF5.:'

Example =9.--295 grams .of the. compound KE2HF+175 grams rof the compound. :KE'c-ie135 grams ofv titanium monoxiderof J+-'200omesh".-par ticle size were mixed together and treated as in Example'l': '560 grams of productiresulted, substantially. equivalent- :to 100 yield of the "com pound':

Other": modes; of applying: the principle of "the :inventionzrmayebe employedgchangejoeingmade as aregards 'the detailsvdescnibed; provided' the features stated in any of the following claims or the equivalent of such be employed.

We therefore particularly point out and distinctly claim as our invention:

1. The method of producing alkali metal fluotitanates in which the titanium has a valence of three which comprises reacting in an inert atmosphere and at a temperature of at least 100 C. titanium monoxide, an alkali metal fluoride and an acid fluoride of the group consisting of sodium, potassium, lithium and ammonium acid fluorides, and recovering the resulting alkali metal fluotitanate of trivalent titanium.

2. The method of producing alkali metal fluotitanates in which the titanium has a valence of three which comprises reacting in an inert atmosphere and at a temperature of about 100"- 125 C. titanium monoxide, an alkali metal fluoride and an acid fluoride of the group consisting of sodium, potassium, lithium and ammonium acid fluorides, subsequently raising the temperature of the resulting mass to about 400-500 C. to complete the reaction, and recovering the resulting alkali metal fluotitanate of trivalent titanium.

3. The method of producing alkali metal fluotitanates in which the titanium has a valence of three which comprises reacting in an inert atmosphere and at a temperature of at least 100 C. titanium monoxide, an alkali metal fluoride and ammonium acid fluoride, and recovering the resulting alkali metal fluotitanate of trivalent titanium.

4. The method of producing alkali metal fluotitanates in which the titanium has a valence of three which comprises reacting in an inert atmosphere and at a temperature of about C. titanium monoxide, potassium fluoride and ammonium acid fluoride, subsequently raising the temperature of the resulting mass to about 400-500 C. to complete the reaction, and recovering the resulting potassium fiuotitanate of trivalent titanium.

5. As a new composition of matter, a titanium compound of the formula MnTinFn" in which M is an alkali metal, n is at least 2 and not over 3, n" is at least 1 and not over 2, n" is at least 6 and not over 8, and in which n+3n=n", said compound being non-hygroscopic and resistant against oxidation.

6. As a new composition, a titanium compound KzTiFe, being non-hygroscopic and resistant against oxidation.

7. As a new composition, a titanium compound KzTizFs, being non hygroscopic and resistant against oxidation.

EUGENE WAINER. SAMUEL Z. CARDON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 921,686 Fitzgerald et a1. May 18, 1909 2,577,130 Kawecki Dec. 4, 1951 OTHER REFERENCES Jones: Inorganic Chem., 1947 ad, page 663, The Blakiston Co., Philadelphia. 

1. THE METHOD OF PRODUCING ALKALI METAL FLUOTITANATES IN WHICH THE TITANIUM HAS A VALENCE OF THREE WHICH COMPRISES REACTING IN AN INERT ATMOSPHERE AND AT A TEMPERATURE OF AT LEAST 100* C. TITANIUM MONOXIDE, AN ALKALI METAL FLUORIDE AND AN ACID FLUORIDE OF THE GROUP CONSISTING OF SODIUM, POTASSIUM, LITHIUM AND AMMONIUM ACID FLUORIDES, AND RECOVERING THE RESULTING ALKALI METAL FLUOTITANTE OF TRIVALENT TITANIUM. 